Luminous level.



E. J.,LORING.'

LUMINOUS LEVEL APPLICATION FILED JUNE 16. l9l9- Patented Oct. 7, 1919.

INVEN TOR ERNEST J. LORING, OF WASHINGTON, DISTRICT OF COLUMBIA LUMINOUS LEVEL.

Specification of Letters Patent.

Patented Oct. 7, 1919.

Application med June 16, 1919. Serial No. 304,694.

(FILED UNDER THE ACT OF MARCH 3, 1883, 22 STAT. L., 626.)

To all whom it may concern Be it known that I, ERNEST J. 'LORING,

a citizen of the United States, stationed at Washington, District of Columbia, have invented an Improvement in Luminous Levels, of which the following is a specification.

The invention described herein may be used by the Government, or any of its ofiicers or employees in prosecution of work for the Government, or by any other person in the United States, without payment of any royalty thereon.

The subject of this inventionis a level, and the invention relates more particularly to a level which is rendered luminous so that the same may be seen at night.

In devices for directing and controlling gun fire, it is desirable that some means be had for illuminating the level at night and such means should be of such character that, while permitting thelevel to be readily seen, will not emit rays of light which may be seen by the enemy. This is best accomplished by placing a strip of luminous ma-- terial beneath the glass tube or vial of the level.

The tubes used in levels are of two characters, viz: The heavy glass tube used'in the more expensive level, which has a slightly curved bore and which is lapped on the inside to make the bore absolutely smooth; and the bent glass tube which is the more usual commercial form, and which is made by bending an ordinary tube of thin glass and sealing the ends thereof after the tube has been filled with the liquid.

\Vith the more expensive form of tube, the luminous strip works fairly well because of the fact that the glass has been rendered slightly cloudy by the lapping of the bore of the tube. In the usual commercial form, the glass of the tube -is clear and the light emitted by the luminous strip appears so brightly that the bubble in the tube cannot be seen. These tubes are of so sharp a curve that lapping thereof is not practical.

The present invention is designed to overcome this effect and to so diffuse the light from the strip as to render the bubble easily discernible. I

a illustrated in the accompanying drawing,

wherein Figure l is a. top plan View of a level con structed in accordance with the invention; and

Fig. 2 is a vertical longitudinal section of the same.

Referring to the drawing by numerals of reference; an ordinary; tubular casing 1 is provided, formed with a sight opening 2, and having apertures 3, 3 formed diametrically thereof adjacent each end for the purpose of permitting fastening means, suc as a screw, to be passed therethrough. The tubular casing is closed at each end by caps 4, 4:. Within the tubular easing are the spaced apart retaining walls 5, 5, between whichis located a glass tube 6 in position to underlie the sight opening 2. The tube is retained against movement longitudinally of the casing by means of the walls 5. A support 6 may be interposed between the bottom of the-tube and casing in order to retain the tube in proper position and a strip 7 of luminou material is placed beneath the tube and held in position by the support, or caused to adhere to the underside of the tube so that the light therefrom may be seen through the tube.

In order that the light from the luminous material may be roperly difi'used so that the bubble 8 can be readily seen, the glass of the tube is slightly clouded in any suitable manner, but preferably by etching on the inside.with hydrofluoric acid or other .like means.

Having described my invention, What I etched on its inner surface, and a strip of 10 claim is: luminous material positioned adjacent said 1. A luminous level including a tube havtube. ing a movable bubble therein, said tube 3. Alumlnous level lncludingatranslucent 5 formed to diffuse light rays passing theretube having a movable bubble therein, and

through and a strip of luminous material a strip of luminous material positioned ad- 15 positioned adjacent said tube. jacen't said tube.

. 2. A luminous level including a glass tube having a movable bubble therein, said tube ERNEST J. LORING. 

